We have measured the branching fraction and photon energy spectrum for the radiative penguin process b → sγ. We find B(b → sγ) = (3.21 ± 0.43 ± 0.27 +0.18 −0.10 ) × 10 −4 , where the errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, E γ = 2.346 ± 0.032 ± 0.011 GeV, and E 2 γ − E γ 2 = 0.0226± 0.0066± 0.0020 GeV 2 , where the errors are statistical and systematic. From the first moment we obtain (in M S, to order 1/M 3 B and β 0 α 2 s ) the HQET parameterΛ = 0.35 ± 0.08 ± 0.10 GeV.